Sanofi vaccine against GI 'superbug' starts phase III

Aims to protect against Clostridium difficile

Sanofi has started phase III testing of a vaccine against a Clostridium difficile, a leading cause of serious gastrointestinal disease with a mortality rate of 8 to 15 per cent.

The spore-forming bacterium - known as C. diff - is fast emerging as a major healthcare-associated infection (HAI) around the world, and recent outbreaks of hypervirulent strains of the organism have caused major problems, particularly as they quickly develop resistance to fluoroquinolone antibiotics.

The risk of C. diff increases with age, antibiotic treatment and time spent in hospitals or nursing homes, where multiple cases can lead to outbreaks, according to Sanofi, which notes that 350,000 patients in the US alone are hospitalised with the infection every year.

Studies have shown that even after cleaning, 49 per cent of surfaces in hospital rooms that have housed a C. diff patient will still be contaminated with the organism or its spores.

The company's vaccines unit Sanofi Pasteur has started a phase III programme called Cdiffense to evaluate the safety, immunogenicity and efficacy of its investigational vaccine in up to 15,000 adults aged over 50 at clinical sites in 17 countries.

The three-year trial is due to start enrolling patients this month and will recruit people who are shortly to go into hospital for a procedure or who have been in hospital for at least 72 hours over the prior 12 months.

The vaccine targets the toxins generated by C. diff, stimulating an immune response which is designed to stop subsequent exposure to the bacterium causing an infection.

"With the emergence of difficult-to-manage strains of C. diff, [infection] has become more frequent, more severe and more difficult to treat in recent years, raising concerns about how to control it and prevent transmission," said John Shiver, senior VP for R&D at Sanofi Pasteur.

"Vaccination could be an efficacious, cost-effective and important public-health measure to protect individuals from C. diff," he added.

Meanwhile, researchers in the UK have developed a simple predictive test to identify patients most at risk of dying from a C. diff infection, raising the possibility of identifying patients who need more intensive therapy and helping to direct antibiotic treatment.